The present invention relates to a process and apparatus for producing magnetic diskette and, more particularly, to a process of and apparatus for producing liners provided in a magnetic diskette such as floppy disc for cleaning the surfaces of the disc and placing the liner on a shell at a desired position thereof
In general, a magnetic diskette comprises a shell composed of upper and lower half, a magnetic disc sheet placed between the shell halves and liners each welded on the shell half.
The liners are composed of a nonwoven fabric sheet and this sheet has the liner form cut, these are used for cleaning the magnetic disc sheet and for preventing the disc sheet surface from debris, etc.
Various methods and apparatus for producing magnetic diskette including such liners, particularly, processes and apparatus for production of such liners and for assembling the liners into the shells have been proposed Some examples of the prior arts are as follows
Japanese Patent Laid-Open No. 61-14895 (1986) discloses a liner production method in which a nonwoven fabric sheet is cut by a device of die and punch to form a disc-like piece, the disk-like piece is transferred to another cutting machine and cut them from a central opening thereby to form a ring-like liner. The liner is welded to a shell. This method uses the die and punch.
The die and the punch are necessary to provide a small gap between the die and punch. Since the nonwoven fabric sheet has very fine fibers therein, so that the gap has to be very small. Therefore it is difficult to cut the sheet without leaving any fibers uncut.
Japanese Patent Laid-Open No. 62-129987 (1987) discloses a method of cutting a nonwoven fabric sheet into a liner. According to the method, the sheet is disposed on a film of synthetic resin which can be melted with heat and has a lower melting point than that of the liner sheet, and heat is applied to the sheet and film along a cutting line to melt the resin and fix the fabric sheet with the melted resin, and then the sheet is press-cut by a means of a die and punch along the melted resin portion, so that the fabric sheet can be cut without defibering or without leaving any fibers uncut. This process is complicated.
Japanese Patent Laid-Open No. 61-162873 (1986) discloses a process of forming liners and assembling the liners into half cartridges. In the process, a series of half-production liners band in which partial outer peripheries of the liners and central openings are shaped is formed from a nonwoven fabric sheet, and then the band is cut to form openings for magnetic heads and separate by cutting between adjacent liners.
The cut-off individual liner is transferred on the half cartridge by a transfer device and fixed thereto. The process and apparatus for carrying out the process are complicated.
Japanese Patent Laid-Open No. 61-278094 (1986) discloses an assembling apparatus for magnetic disc cartridges. The apparatus includes liner production apparatus wherein a nonwoven sheet is cut into a final liner profile with a die roller and an anvil roller, the cut liner is sucked on the anvil roller, transferred to a cartridge casing by a robot and then spot-welded thereto for preliminary fixing. The complete profile of the liner has intersections of a straight line and another straight line, or of a straight line and a curved line. Upon the cutting, at such intersections, uncut fibers of a nonwoven fabric sheet for the liner are likely to be left. Further in case that the liner formed by the cutter roller and the anvil roller is directly transferred to the shell, it is difficult to place the liner on the shell at a correct position, because the nonwoven fabric sheet for liners is very soft and easy to deform so that a distance between the cutting position and a transfer position, for example, is not constant and a relative position of the transfer head and the liner held by the transfer head is not constant.
Japanese Patent Laid-Open No. 61-188879 (1986) is similar to the above Laid-Open and further including, before cutting the sheet into a liner, a heat seal step for forming heat seal portion along the configuration of the liner. The heat seal can be carried out pressing a heat seal roll on the nonwoven fabric sheet on an anvil roller. The liner which the heat seal is effected does not disperse dusts from cut edge portions of the liner.
Japanese Patent Laid-Open No. 62-152696 (1987) discloses a method of production of liners. According to the method, two nonwoven fabric sheets are put on each other. The piled sheets are cut to form a series of semi-production liners each having central opening and an outer periphery formed by 4 slits and the sheets are separated. Each sheet is cut into an individual liner, and then the liner is cut to form a window opening for magnetic head. This process also is complicated.